磁致伸缩导波激励端偏置磁场的等效方法

Equivalent method of bias magnetic field for generating guided waves based on magnetostrictive effect

从磁致伸缩效应的基本原理出发,研究磁致伸缩换能效率与偏置磁场的对应关系,得到了换能效率的评价方法和用于评价永久磁铁及直流磁化线圈磁化效果的等效方法.该方法由永久磁化器和直流线圈同时提供方向相反的偏置磁场,通过调节线圈的电流,得到磁致伸缩换能效率与电流之间的关系;再利用换能效率仅与偏置磁场的大小有关而与偏置磁场的方向无关的对称特性,确定叠加偏置磁场的平衡点即叠加磁场强度为零的点,从而得到永久磁化器和直流线圈的等效关系.最后通过实验对等效关系进行了验证.

From the basic principle of the magnetostrictive effect, the evaluating method of the conver- sion efficiency and the equivalent method of the two types of magnetizers were obtained through stud- ying the relation between the conversion efficiency and the bias magnetic field. When the permanent magnet was used to magnetize the specimen in one direction and the DC magnetizing coil provides the bias magnetic field in the opposite direction at the same time, the equivalent relation between the con- version efficiency and the bias current were obtained by regulating the current. Because the conversion efficiency is only dependent on the strength and not on the direction of the bias magnetic field, the equilibrium point （i. e. the state when the superimposed magnetic intensity is zero） was determined based on the symmetrical characteristic. Then the equivalent relation between the permanent magnet magnetizer and the DC magnetizing coil was obtained. At last, the equivalent relation was verified by experiment.